In recent years, the needs of large telecommunications subscribers have evolved from a demand for conventional long distance service to a need for high-bandwidth data transmission capability. As the sophistication of large telecommunications subscribers has advanced, so has their capability to monitor the quality of services they receive. Many large subscribers of data communications services now have the ability to detect deviations in the quality of service they receive, often in advance of any detection by the carrier providing the service.
Present-day performance monitoring systems employed by telecommunications carriers typically operate by providing an alarm indication when a particular condition (attribute) exhibited by a network element crosses an alarm threshold. Such systems do not necessarily provide the most practical solution to the problem of monitoring network performance. In practice, setting alarm thresholds to a low setting to track trouble signatures will yield a large number of alarms, often overwhelming network technicians. On the other hand, setting alarm thresholds to a relatively high setting will prevent detection of a network element undergoing a gradual failure.
Thus, there is a need for a network monitoring technique that affords a telecommunications carrier the ability to track the performance of its network by detecting the gradual performance degradation of networks elements over time.